diff --git a/db/zm_update-1.31.31.sql b/db/zm_update-1.31.31.sql
new file mode 100644
index 000000000..66e25f95c
--- /dev/null
+++ b/db/zm_update-1.31.31.sql
@@ -0,0 +1 @@
+ALTER TABLE Storage MODIFY DiskSpace BIGINT default NULL;